About JAPAN AI
JAPAN AI, Inc. was established in April 2023 as a group company of Geniee, Inc., a publicly listed company, with the aim of dramatically enhancing the potential of working people through AI technology. We leverage cutting-edge AI technology to drive research and development both domestically and internationally.

We focus particularly on the development of AI agents, providing innovative products and solutions that utilize large language models (LLM). This enables us to improve productivity and operational efficiency across various industries.

JAPAN AI leverages the advantages of being a startup, allowing for flexible and rapid decision-making, and quickly adopting the latest technologies to provide optimal solutions for our clients. Additionally, our diverse team with an international perspective enhances our competitiveness in the global market.

We aim to create new value and contribute to the progress of society as a whole through the transformative power of AI. Let's lead innovation through AI and create a future where technology enables people to achieve more.

Related URLs

• Our Website
• Company Introduction Materials
• Tech Blog

Why We're Hiring
JAPAN AI Inc. is experiencing rapid growth through product development leveraging Generative AI. As AI technologies and their social implementation accelerate, the importance of scalable and robust backend development for our innovative AI product suite—including JAPAN AI CHAT, JAPAN AI Speech, and JAPAN AI AGENT—continues to increase.

We are hiring a Backend Engineer to accelerate product growth.

Position
Generative Backend Engineer

Role : Member

Role Summary
As a Backend Engineer, you will lead the design, development, and operation of backend systems for JAPAN AI's product suite. You will design and build scalable, robust backend architectures and technical foundations for next-generation products utilizing AI agent technologies and large language models. We expect you to contribute to enhancing product value through collaboration with cross-functional teams.

Why You'll Love This Role

• Cutting-edge technology challenges:

• Work with state-of-the-art technologies such as large language models and generative AI

• Complex SaaS product development:

• Build high-value expertise by solving challenges in high-traffic B2B products

• Socially impactful product development:

• Contribute to solving real-world problems for society and enterprises using AI technology

• Collaboration with diverse talent:

• Work alongside talented members from diverse backgrounds in a stimulating growth environment

• Balance of personal and organizational growth:

• Thrive in a dynamic environment that balances individual growth with organizational development

Job Description

• AI Product Development

• Design, develop, and operate backend systems for AI products

• Implement AI agent systems utilizing large language models (LLMs)
• Develop APIs for real-time speech processing and speech synthesis systems

• Build and optimize natural language processing pipelines

• System Architecture & Infrastructure

• Design distributed systems using microservices architecture

• Design and implement scalable APIs for high-traffic scenarios
• Containerization and Kubernetes operations on GCP

• Database design and query optimization for large-scale data processing

• Development Process & Quality Improvement

• Build and improve CI/CD pipelines

• Promote code reviews and test automation
• Build monitoring and log analysis systems

• Implement and operate based on security requirements

• Machine Learning & AI Integration

• Integrate and deploy machine learning models to production environments

• Build and operate MLOps pipelines
• Optimize inference API performance and reduce latency

• Develop A/B testing infrastructure and support data analysis

• Team Collaboration & Technical Leadership

• Collaborate with cross-functional teams (designers, product managers, project managers)

• Participate in technical selection and architecture decisions
• Research new technologies, build prototypes, and conduct technical validation
• Improve and automate development processes

Team Structure
Approximately 70 Members In The Development Organization, Divided Into

• Client Solution Development
• In-house AI SaaS Development
• Common platform development (Infrastructure / Data / DX / AI R&D)

Required Qualifications
We Are Looking For Candidates With

• Bachelor's degree in Computer Science, Software Engineering, Artificial Intelligence, Machine Learning, Mathematics, Physics, or related fields, or equivalent practical experience
• 5+ years of application development experience using Python
• 3+ years of experience developing complex SaaS products or high-traffic B2B products
• 3+ years of experience with cloud services (AWS, GCP, Azure) and container technologies (Docker, Kubernetes)
• Experience working at startups or growth-stage companies, or equivalent environments
• Knowledge of and passion for AI-related technologies

• Language requirements (either):

• Japanese: Fluent (able to discuss product development without misunderstandings)

• English: Business level

Preferred Qualifications
Candidates with the following experience or skills will be highly regarded:

• Experience building systems utilizing natural language processing or machine learning
• Experience developing machine learning models with Python, TensorFlow, or PyTorch
• Experience with chatbot, speech recognition systems, or AI agent development
• Experience launching new businesses/products from the 0→1 phase
• Full-stack application development experience
• Bilingual (Japanese/English)

Tech Stack
Languages: Python (for framework development), TypeScript / React / (frontend) / NX

Infrastructure: GCP (containers / Kubernetes), Docker

Tools: Slack, Confluence, Linear, Google Workspace, GitHub, Notion, etc.

Work Environment: Mac (Apple Silicon), dual monitors available

Learning and Development Support

• AI Tool Usage Support:

• Company covers the cost of using AI tools such as JAPAN AI SaaS services, Curosor, CharGPT, Claude, etc.

• Development Tool Support:

• If a desired development tool is paid, the cost is covered (up to 30,000 yen per year)

• Book Purchase Assistance:

• Company covers the cost of purchasing books for learning, such as technical books (up to 30,000 yen per half-year)

• Language Learning / Qualification Support:

• Company covers the cost of Japanese or English learning programs and qualification acquisition

• Refresh Allowance:

• Company covers the cost of services used for personal refreshment (up to 5,000 yen per month)

• e.g., gym, yoga, chiropractic, aquarium, movies, theme park tickets, etc.

• Housing Allowance:

• Housing allowance provided for those living in designated areas (up to 30,000 yen per month)

Work Style
Hybrid Work: 3 days in office, 2 days remote

Flexible working hours: Core time is negotiable

Flexibility: Future consideration for more flexible work styles is possible

Selection Process
CV Screening → Coding test → Multiple Interviews → Final Interview

(Reference checks are required before the final interview.)

職種 / 募集ポジション
【JAPAN AI】Backend Engineer

雇用形態
正社員

給与
年収

Salary: ¥571,429–¥1,142,857/month Base: ¥410,915–¥821,830 Fixed OT: ¥160,514–¥321,027 for 50h OT beyond 50h paid separately Reviews: 2x/year (Apr, Oct), Bonuses: 2x/year (May, Nov) SO available

勤務地

• Sumitomo Fudosan Shinjuku Oak Tower, 5th/6th Floor, Nishi-Shinjuku, Shinjuku-ku, Tokyo 地図で確認

会社情報

会社名
株式会社ジーニー

事業内容
・広告プラットフォーム事業 ・マーケティングSaaS事業 ・デジタルPR事業

設立年月日
2010年4月14日

代表者
代表取締役社長 工藤 智昭

資本金
100百万円(連結、2025年3月末現在)

従業員数
877名(連結、2025年3月末現在)

本社所在地
東京都新宿区西新宿6-8-1 住友不動産新宿オークタワー5/6階

就業時間
10:00~19:00 ※土日祝は休業日となります ※出向の場合は、出向先の規程に準じます

福利厚生
【待遇・福利厚生】 ・書籍購入補助(半期 30,000円まで) ・リフレッシュ手当(毎月 5,000円まで) ・部活動手当(毎月5,000円まで) ・家賃手当(当社指定の駅を対象とし毎月30,000円まで) ・シャッフルランチ/ディナー(四半期に一度ランチ1,000円まで、ディナー5,000円まで) ・資格取得支援制度、英語学習支援制度(業務に必要な場合のみ) ・リフレッシュ休暇制度(3年間継続勤務した社員へ毎年付与される特別休暇 2日) ・定期健康診断(年1回) ・従業員持株会 ・書籍購入補助(半期 30,000円まで) ・リフレッシュ手当(毎月 5,000円まで) ・部活動手当(毎月5,000円まで) ・シャッフルランチ/ディナー(四半期に一度ランチ1,000円まで、ディナー5,000円まで) ・リフレッシュ休暇制度(3年間継続勤務した社員へ毎年付与される特別休暇 2日) ・定期健康診断(年1回) 【保険】 ・社会保険完備 【諸手当】 ・交通費全額支給

代表プロフィール
早稲田大学大学院卒業後、株式会社リクルート(現 株式会社リクルートホールディングス)へ入社。2010年4月株式会社ジーニーを創業、代表取締役社長に就任。2023年4月には戦略的AIカンパニーJAPAN AI株式会社を設立し、同社の代表取締役社長を兼任している。

企業成長ランキング
■ Financial Times社発表のアジア成長企業ランキング2020を受賞 Financial Times社とStatista社が、アジア太平洋地域12カ国5,000万以上の企業を対象に実施した調査で、飛躍的活躍を遂げた企業500社に選出されました。

休日休暇
完全週休二日制 所定休日:土・日・祝日 休暇:年次有給休暇、夏季休暇(3日)、年末年始休暇(12月31日〜1月3日)、慶弔休暇

グループ会社
CATS株式会社(日本) JAPAN AI株式会社(日本) ソーシャルワイヤー株式会社(日本) Geniee International Pte., Ltd.(シンガポール) Geniee Vietnam Co., Ltd.(ベトナム) PT. Geniee Technology Indonesia(インドネシア) PT. Adstars Media Pariwara(インドネシア) Zelto,Inc.(米国) AdPushup Software India Pvt Ltd.(インド)

備考
・試用期間 正社員/契約社員:1か月 ・受動喫煙対策 敷地内禁煙(屋外に喫煙場所設置) ・従事すべき業務の変更の範囲 会社の定める業務 ・就業の場所の変更の範囲 会社の定める場所 ・有期労働契約を更新する場合の基準に関する事項(通算契約期間又は更新回数の上限を含む) 更新の上限なし